A personal messaging unit (sometimes referred to herein as a "PMU") such as a pager subscribes to a messaging service for the purpose of receiving messages that can originate from a number of sources. Most personal messages originate from telephones, but other messages can originate from computers, news, stock reporting services and from various other sources.
Typically, the user of a PMU pays a flat monthly fee to the messaging service. For that fee, the user (referred to hereinafter as a "subscriber") is permitted to receive a certain number of messages per billing period, with an extra charge for each message which exceeds that number. Thus, a subscriber who receives more messages than he anticipated may receive a correspondingly larger bill.
This problem has become aggravated by the introduction of new messaging services, such as E-mail notification. In this type of service, whenever an E-mail message is sent to a subscriber's computer, the subscriber is notified of that event by a brief message that is transmitted to his PMU. A subscriber who receives a large number of unsolicited E-mail messages may find that his monthly bill greatly exceeds his expectations.
It has been proposed to limit a subscriber's cost by programming his PMU to count the number of incoming messages and to stop displaying received messages when a certain number have been received. For some subscribers, this solution is adequate. Other subscribers need more flexibility to ensure that they can control their costs without missing messages that are important to them.